If you think losing weight is all about counting calories and eating less, think again, says Terry Fairclough, a renowned personal trainer and co-founder of Your Body Programme. Lots of people are debating the best diet for weight loss: Should you count calories? Should your diet be low fat, low carb, or high protein? Should you fast, or have small frequent meals?

Sure, cutting calories can make you lose weight, but it might not be the fat loss you’re after. Our diets are usually larger than needed, so most of us could benefit from eating a bit less. However, drastically reducing calories isn’t the answer, and I’ve seen many people mistakenly believe this.

When your body breaks down carbohydrates, they turn into glucose, the main fuel source for our cells. If your body doesn’t use this glucose, it stores it as glycogen in your muscles and liver, along with water. And when you cut calories, what you’re really losing is this stored carbohydrate and water—not fat.

Long-term calorie cuts can cause your body to panic, clinging to fat and breaking down protein instead. This is counterproductive since more protein helps burn more fat. So, it’s crucial to consume enough calories packed with fats, carbs, and proteins.

Contrary to popular belief, you do need fat even when trying to lose it. Fat is a critical and lasting fuel source with twice as much energy-per-gram compared to carbs or protein. It’s also stored in muscles, providing fuel during exercise. Without fat, you just won’t have the energy to burn off unwanted fat.

Cutting calories too much and depriving yourself of nutrients can lead to deficiencies that affect your overall health, including your immune and digestive systems. This can lead to fatigue, malnutrition, osteoporosis, anemia, and hormonal issues, amongst others. Extreme calorie restriction also leads to increased stress and the release of cortisol, which can cause long-term fat storage, especially around the belly. It also impacts your metabolism and digestive functions.

Not eating enough can also wreck your sleep. Low blood sugar triggers adrenaline, waking you up and affecting your liver, immunity, and overall productivity, often resulting in weight gain. Some bodybuilders swing between restricting and increasing calories, sometimes with adverse effects when done incorrectly.

Continual calorie cutting can break down your body and hamper your metabolism to the point where losing weight feels impossible because your body, in survival mode, stores any excess calories as fat.

The key is to eat the right amount of calories, carbs, fats, and proteins for your specific needs, considering your body type, goals, activity level, and other personal factors. That’s why I started the Your Body Programme—to help individuals determine what their bodies need.

Rather than restricting calories, my program has shown that increasing caloric intake, balanced with proper nutrition, can actually promote fat loss. Focus on eating lean proteins like chicken, eggs, and tofu, healthy carbs from fruits, vegetables, and whole grains, and healthy fats from sources like avocados and nuts.

You only have one body, so nourish it well to keep your metabolism going strong.